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An optical sensor for discriminating the chemical compositions and sizes of plastic particles in water based on water-soluble networks consisting of polyhedral oligomeric silsesquioxane presenting dual-color luminescence
摘要： Luminescent water-soluble networks containing the coumarin luminophore were prepared by using polyhedral oligomeric silsesquioxane (POSS) as a cross-linking point, and the optical properties of these networks in the presence and absence of various particles in water were monitored. From the emission measurements, we found that water dispersions of the POSS networks showed bimodal light-emission bands, namely in the blue and yellow regions. In particular, enhancement of the emission band in the blue region was observed upon the introduction of polystyrene particles (PSPs), poly(lactic acid) particles (PLAPs) and poly(methyl methacrylate) particles (PMMAPs), followed by changes in the color of the luminescence of the samples. In contrast, hardly any significant changes were observed when silica particles (SPs) were added. Moreover, plastic particles with diameters of less than 1 mm drastically affected the optical properties of the networks. Thus according to these results, the presence of plastic particles with sub-micron dimensions in water could be detected by changes in the color of light emitted from the POSS network from yellow to blue. Note that silica species, such as sand or rock particles, can be ignored in this system. From mechanistic studies, it was revealed that the blue-light-emission band was enhanced when the networks were adsorbed onto the surfaces of the particles. These characteristics are applicable for constructing a facile fluorescence sensor for detecting water pollution, especially nanosized plastics, denoted here as nanoplastics.
关键词： optical sensor,plastic particles,polyhedral oligomeric silsesquioxane,water-soluble networks,dual-color luminescence
更新于2025-09-16 10:30:52
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Accuracy and biases in predicting the chemical and physical traits of many types of cheeses using different visible and near-infrared spectroscopic techniques and spectrum intervals
摘要： Near-infrared spectroscopy (NIRS) has been widely used to determine various composition traits of many dairy products in the industry. In the last few years, near-infrared (NIR) instruments have become more and more accessible, and now, portable devices can be easily used in the field, allowing the direct measurement of important quality traits. However, the comparison of the predictive performances of different NIR instruments is not simple, and the literature is lacking. These instruments may use different wavelength intervals and calibration procedures, making it difficult to establish whether differences are due to the spectral interval, the chemometric approach, or the instrument’s technology. Hence, the aims of this study were (1) to evaluate the prediction accuracy of chemical contents (5 traits), pH, texture (2 traits), and color (5 traits) of 37 categories of cheese; (2) to compare 3 instruments [2 benchtop, working in reflectance (R) and transmittance (T) mode (NIRS-R and NIRS-T, respectively) and 1 portable device (VisNIRS-R)], using their entire spectral ranges (1100–2498, 850–1048, and 350–1830 nm, respectively, for NIRS-R, NIRS-T and VisNIRS-R); (3) to examine different wavelength intervals of the spectrum within instrument, comparing also the common intervals among the 3 instruments; and (4) to determine the presence of bias in predicted traits for specific cheese categories. A Bayesian approach was used to develop 8 calibration models for each of 13 traits. This study confirmed that NIR spectroscopy can be used to predict the chemical composition of a large number of different cheeses, whereas pH and texture traits were poorly predicted. Color showed variable predictability, according to the trait considered, the instrument used, and, within instrument, according to the wavelength intervals. The predictive performance of the VisNIRS-R portable device was generally better than the 2 laboratory NIRS instruments, whether with the entire spectrum or selected intervals. The VisNIRS-R was found suitable for analyzing chemical composition in real time, without the need for sample uptake and processing. Our results also indicated that instrument technology is much more important than the NIR spectral range for accurate prediction equations, but the visible range is useful when predicting color traits, other than lightness. Specifically for certain categories (i.e., caprine, moldy, and fresh cheeses), dedicated calibrations seem to be needed to obtain unbiased and more accurate results.
关键词： chemometric,texture trait,cheese quality,water-soluble protein,Bayesian calibration
更新于2025-09-12 10:27:22
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Simple Synthesis Method and Characterizations of Aggregation-Free Cysteamine Capped PbS Quantum Dot
摘要： Quantum dots have diverse chemical properties with di?erent ligands attached on the surface. The cysteamine has been used as a ligand for various quantum dots because it has high solubility in water, and it facilitates binding of quantum dot and gold surface. However, the hydrogen bonds in cysteamine cause aggregation of the cysteamine capped quantum dots. In this study, we suggested a simple synthesis method of aggregation-free PbS quantum dot and analyzed the electric and optical properties of the synthesized quantum dot. This study on aggregation-free cysteamine capped quantum dots has the potential to develop advanced quantum dot-based sensor technologies, including biomedical imaging and environmental sensors.
关键词： aggregation-free,cysteamine capped quantum dots,lead sulfide quantum dots,water-soluble quantum dots
更新于2025-09-12 10:27:22
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Water Soluble and Bright Luminescent Cesium Lead Bromide Perovskite Quantum Dot-Polymer Composites for Tumor-Derived Exosomes Imaging
摘要： Cesium-lead-halide perovskite quantum dots (PQDs), are a highly promising class of next-generation optical material for bio-imaging applications. Herein, we present a nanocomposite strategy for the design of water soluble, highly luminescence CsPbBr3 PQD nanocomposites without modifying the crystal symmetry and photoluminescence (PL) property. Water soluble PQDs are reproducibly synthesized via encapsulating CsPbBr3 PQDs with polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (PS-PEB-PS) and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol (PEG-PPG-PEG). In the reported design, the polystyrene triblock polymers strongly interact with the hydrophobic parts of PQDs and the water-soluble PEG moiety acts as protection layer to effectively prevent degradation of PQDs in water. Outer shell PEG layer also helps to develop biocompatible PQDs. Reported data indicate that encapsulating CsPbBr3 PQDs with polymer helps to improve the photoluminescence quantum yield (PLQY) from 83% to 88%, which may be due to decrease in the surface defects after the effective polymer coating. Experimental data show that PL intensity from CsPbBr3 PQD nanocomposites remain unchanged even after 30 days of exposure in air. Similarly, reported data indicate that nanocomposites retain their luminescence properties in water for first 8 days and then decreases slowly to 60% of its initial PL intensity after one month. On the other hand, the PL emission for the PQD without polymer encapsulation is completely quenched within few hours. Exosomes are highly promising avenue for accessing tumor type and stage and to monitor cancer treatment response. Reported data reveal that anti-CD63 antibody attached PQD nanocomposites are capable of tracking of triple negative MDA-MB-231 breast tumor derived exosomes via binding using anti- CD63 antibody and selective green luminescence imaging using PQD nanocomposites.
关键词： selective imaging of exosomes,Triple negative breast tumor derived exosomes,water soluble perovskite nanocomposites,Air stable CsPbBr3 quantum dots,Green luminescence imaging
更新于2025-09-11 14:15:04
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Aqueous synthesis of lead halide perovskite nanocrystals with high water stability and bright photoluminescence
摘要： Lead halide perovskites nanocrystals (NCs) have attracted intense attentions because of their excellent optoelectronic properties. The ionic nature of halide perovskites makes them highly vulnerable to water. Encapsulation of perovskite NCs with inorganic or organic materials have been reported to enhance the stability, however they often suffer from large aggregation size, low water-solubility and difficulty for further surface functionalization. Here, we report a facile aqueous process to synthesize water-soluble CsPbBr3/Cs4PbBr6 NCs with the assistance of fluorocarbon agent, which features a novel mechanism of the perovskite crystallization at oil/water interface and direct perovskite NCs/fluorocarbon agent self-assembly in aqueous environment. The products exhibit a high absolute photoluminescence quantum yield (PLQY) of ~80% in water with the photoluminescence lasting for weeks. Through successive ionic layer adsorption and reaction (SILAR), BaSO4 was further applied to encapsulate the NCs, and greatly enhanced their stability in phosphate buffered saline solutions. The high stability in water and saline solution, high PLQY and tunable emission wavelength, together with the successful demonstration of brain tissue labelling and photoluminescence under X-ray excitation, make our perovskite NCs a promising choice for X-ray fluorescent bio-labels.
关键词： CsPbBr3,water soluble,multicolor,perovskite,nanocrystals
更新于2025-09-09 09:28:46
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Synthesis, photodynamic activities, and cytotoxicity of new water-soluble cationic gallium(III) and zinc(II) phthalocyanines
摘要： The cationic Ga(III) and Zn(II) phthalocyanines carrying N-methyl-pyridinium groups at eight peripheral β-positionshave been synthesized. These complexes are highly soluble in dimethyl sulfoxide (DMSO) and moderately soluble in water and phosphate buffered saline (PBS); both Ga(III)Cl and Zn(II) complexes have shown no aggregation in water up to 1.2×10-4 and 1.5×10-5 M, respectively. A higher water-solubility of Ga(III)Cl complex as compared to Zn(II) complex is ascribed to the presence of an axially coordinated chloride. The spectroscopic properties, photogeneration of singlet oxygen (1O2), and cytotoxicity of these complexes have been investigated. The absolute quantum yields (???absolute) for the photogeneration of singlet oxygen using Ga(III)Cl and Zn(II) complexes have been determined to be 4.4 and 5.3 %, respectively, in DMSO solution. The cytotoxicity and intracellular sites of localization of Ga(III)Cl and Zn(II) complexes have been evaluated in human HEp2 cells. Both complexes, localized intracellularly in multiple organelles, have shown no cytotoxicity in the dark. Upon exposure to a low light dose (1.5 J/cm2), however, Zn(II) complex has exhibited a high photocytotoxicity. The result suggests that Zn(II) complex can be considered as a potential photosensitizer for Photodynamic therapy (PDT).
关键词： PDT,Water-soluble,singlet oxygen,Phthelocyanine
更新于2025-09-09 09:28:46
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Preparation of water-soluble asphalt carbon dots and hyperchromic effect to Cr (VI)
摘要： Water-soluble asphalt carbon dots（W-CDs）was prepared from medium - temperature coal tar pitch as raw material, via mixed acid oxidation，alkali solubilization and acid precipitation method. It was observed that as-prepared W-CDs were irregular particles with good water dispersibility and the particle size was controlled by the pH of the acid precipitation solution by a polarizing microscope . Infrared spectroscopy confirmed that the surface of the W-CDs was functionalized by hydrophilic and color-promoting functional groups, which had good water solubility; the thermal weight loss proved to be good thermal stability below 200°C; the fluorescence spectrum proved that the fluorescence emission peak position of the carbon dots appears red shift with increase of excitation wavelength, with fluorescence conversion property, and its emission light intensity decreases, belonging to non-resonant fluorescence type of direct jump fluorescence; UV spectrum proves that the addition of W-CDs can be chromium (VI) CrO4 2- content The detection limit was increased from milligram to microgram; the molar absorptivity of CrO4 2- was increased by 4 times. The experimentally optimized W-CDs-ultraviolet-viscometry method for measuring CrO4 2- conditions: W-CDs to chromium ratio of 8:2, pH of 8, hexamethylenetetramine as a surfactant, and the solution was allowed to stand at room temperature for 45 min.
关键词： hyperchromic effect,Cr (Ⅵ),UV-vis spectrophotometry,Water-soluble asphalt carbon dots
更新于2025-09-04 15:30:14